Spark-plug



D. S. HENVNEY.

SPARK PLUG.

APPLICATION FILED 0cT.4. I9I9.

Patented oct. 4,l 1921a ATTORNEY UNITED STATES DAVID S. HENNEY, 0F MONTCLAIR, NEW JERSEY.

SPARK-PLUG.

Specification of Letters Patent.

Patented Oct. 4, 1921.

lApplication led October 4, 1919. Serial No. 328,402.

T o all 'whomt may concern:

Be it known that I, DAVID S. HENNEY, a citizen of the United States, residin at Montclair, in the county of Essex and tate of New Jersey, have invented certain new and useful Improvements in Spark-Plugs, of which the following is a specification.

This invention relates to spark plugs, and one of the objects of the invention is to provide a new and im roved device ofthe above character, whic will be simple in construction, compression proof, and ossessed of a multiplicity of sparking points.

Another object of the invention is to provide a spark plug whichwill be watery, and oil proof, and practically indestructible.

Other objects and aims of the invention, more or less specific than those referred to above, will be in part obvious and in part point/ed out in thecourse of the following description of the elements, combinations, arrangements of parts and applications of principles, constituting the invention; and the scope of protection contemplated will be indicated in the appended claims.

In'the accompanying drawing, wherein I have illustrated preferred forms of embodiment of my invention:

Figure 1 is a vertical sectional view taken through a spark plug constructed in accordance with my invention; and

IFig. 2 is a similar view showing a different arrangement of the electrodes.

Referring now to the drawing for a more detailed description of the invention, the reference numeral 1 denotes a central metallic rod or spindle, having fixed to its lower end a hollow spherically formed electrode 2.

Riveted on, or otherwise fixed upon the spindle 1 is a shoulder or abutment 3. Wrapped about the spindle 1 is a strip of insulating material, preferably mica, said strip being wrapped tightly about the spindle so that several layers will be positioned thereon, as indicated at 4.

Positioned about the mica covering, at

' its lower end, is a bushing 5, preferably formed of a high heat resisting insulating material. The lower end of the bushing, as well as the mica covering 4 of the spindle 1, rests upon the shoulder or abutment 3.

The reference numeral 6 denotes a metallic shell having an aperture 7 through which extends the spindle 1 and its mica covering 3. The shell 6 is threaded at 8,

as is usual in spark plug construction, so that it can be threaded into the engine cylinder, the shellterminating at 9 in the horizontal plane of the greatest diameter of the electrode 2, so that a circular spark gap 10 is provided entirely around the lower portion of the spark plug.

Surrounding the mica covering 4, and resting upon the upper wall 11 of the shell 6, is an insulator 12. This insulator is preferably formed of a plastic material which can be molded about the parts in the position shown, and which will thereafter' harden into a non-porous, stone-like material, similar to porcelain. The material which I have successfully used in this relation is called porcelute, a plastic composition which quickly dries to a hard non-porous porcelain-like stone.

Positioned above the insulator 11, and encircling the spindle 1, is a washer 13, which is preferably formed of fiber, or mica, and upon this washer is positioned a copper washer 14. Positioned upon the upper threaded end 15 of the spindle 1 is a brass nut 16. It will be understood that the connection between the. spark plug is made between the brass nut 16 and the copper washer 14.

Having thus described the construction of my improved spark plug, the manner in which I assemble the same is as follows: Spindle 2 is first wrapped laterally with a mica sheet, the bushing 5 is then slipped on until it rests upon the shoulder 3 of the spindle. The shell 6 is then slipped on, and the mica covering above the shell is coated with the aforesaid plastic composition. The mica of fiber washer 13, and the washer 14 and nut 15 are then positioned upon the upper endof the spindle, as shown, and the brass nut is drawn up tightly; the parts being allowed to rest in the position shown, until the plastic material has become hardened, which, with the material I prefer to use as above stated, usually takes about forty-eight hours.

In the embodiment of the invention .shown in Fig. 2, the cylindrically formed electrode 2 is omitted, and the-lower end of the shell 6 is closed by a conically shaped wall 17 provided with a plurality of apertures 18, a spark gap 19 being formed between the electrode 2O and the apex 21 of the' coneshaped wall 17.

It will accordingly be seen that I have provided a spark plug well adapted to attain, among others, all the aims and objects above pointed out, in an extremely simple yet elicient manner. Inasmuch as a circular spark gap is provided at the lower end of the plug, a multiplicity of sparking points is provided. The plug in both embodiments of my invention are self-cleaning, inasmuch as it will be noted explosion chambers 22 are provided behind the firing `point, so that the firing points are continually wiped or washed by the egress or exit of gas under compression, and by particles of carbon blown past these parts.

On account of blowing the llame into the cylinder because of the small compression chamber, and the compressed gas within the compression chamber exploding before the charge in the cylinder proper is exploded, a lower grade of explosive mixture can be utilized, and the use of my spark plug is therefore more economical than spark plugs as hitherto provided.

It will be noted that the spark plug is substantiallya one piece plug, inasmuch as the plastic compound l2 when once positioned makes it practically impossible to dissociate the parts of the plug except those at the upper end, and that by 'reason of the construction the plug is substantially compression proof. The plug is also practically indestructible and water and dust proof.

As many changes could be made in this construction without departing from the scope of the following claims, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative only and not in a limiting sense.

Having thus described my invention what claim as new and desire to secure by Letters Patent is 1. In a device of the class described, the combination of a metallic shell, of a metallic spindle extending therethrough and provided at its lower end with an electrode, which forms a spark gap with the lower edge of the shell, a covering of insulating material comprising a strip of mica wrapped around the spindle, said covering extendmg through the shell into the interior thereof, a should-er provided upon the spindle upon which said covering rests, a bushing of insulating material positioned between said shoulder and the inner surface of the upper wall of said shell, and an insulator formed of plastic material molded about the insulating covering exteriorly of the shell and restin upon the upper wall of the shell.

2. n a device of the class described, the combination with a metallic shell provided with a centrally disposed opening in its upper wall, a spindle extending through said opening, a protective covering for said spindle, comprising a plurality of layers of mica formed by winding a sheet of mica thereabout, said protective covering extending through said aperture into the interior of the shell, said spindle having a shoulder upon which rests said protective covering, a bushing ofv an insulating material surrounding said protective covering and extending between said shoulder and the inner surface of the upper wall of said shell, a spherically formed hollow electrode carried upon the upper end of said shell and having its major horizontal axis disposed in a plane occupied by the lower end of said shell, so as to form a circular spark gap, an insulator positioned about said protective covering and resting upon the upper wall of said shell, said insulator being comprised of a plastic material which is positioned upon said protective covering and allowed to harden, a washer positioned above said insulator and encircling said spindle, and cable connecting means mounted upon the upper end of said spindle.

3. In a device of the class described, the combination with a metallic shell, having a circular opening provided in its upper wall, a metallic spindle extending through said opening into the interior of said shell, and having at its lower end a spherically formed hollow electrode, the axis of which lies in the same horizontal plane occupied by the lower end of the shell, so that a circular spark gap is .provided between said electrode and the lower` end of the shell, said shell being provided with a chamber above said electrode, a covering of insulating material for said spindle comprising a sheet of mica wrapped thereabout, so as to provide several layers thereof, Said insulating covering extending into the chamber of said shell, said spindle being provided with a shoulder upon which the lower end of said insulating covering rests, a bushing of insulating material surrounding said insulating covering and interposed between said shoulder and the lower surface of the upper wall of said electrode, an insulator composed of a moldable plastic material positioned exteriorly of said insulating covering and engaging the upper surface of said shell, an insulating washer encircling said spindle and resting upon the upper end of-said insulating covering and said exterior insulator, a metallic washer positioned above said insulating washer and a nut threaded upon the upper end of said spindle.

In testimony whereof I aiiix my signature in the presence of two witnesses.

DAVID S. HEN N EY.

Witnesses:

lEMMA WEINBERG, CHARLES H. WILSON. 

